Well drilling bit



March 1, 1932. e. e. CHALMERS WELL DRILLING BI'I Filed Oct. 5, 1929 2Sheets-Sheet 1 G. G. CHALMERS March 1, 1932.

' WELL DRILLING BIT Filed Oct. 5, 1929 2 Sheets-Sheet Patented Mar. 1,1932 UNITED STATES PATENT OFFICE GEORGE G. GHALMEIRS, OF HUNTINGTONBEACH, CALIFORNIA WELL DRILLING BIT Application filed October. 5, 1929.Serial No. 397,568.

1 in or through the casing; When it becomes,

necessary to replace or repair a drilling tool, the entire drillsteinmust be withdrawn from the well. The drill stem isuncoupled' as itis withdrawnand the lengths or stands of 15 pipe are stacked in thederrick. The withdrawing of the drill stem and the uncoupling of thestands of drill pipe requiremuch time and. are therefore costlyoperations. Further, to resume drilling the drill stem-must be 59 againcoupled together and lowered into the well.

Itis a general object of the invention to provide a well drilling bitthat is adapted tobe operated at. the lower end ofthe-Well casing. Thebit provided by this invention is adapted to be operated at the lowerend of a tubular. member, say, the usual well casing, and does notnecessitate employing a drill stem. g

Another object of the invention. is to provide a drilling bit of thecharacter mentioned which can .be readily attached to a shoe at thelower end of the well casing within a well and may be detached from theshoe when desired.

Another object of the invention is to provide a well tool of thecharacter mentioned that is adapted to drill a holewhich will J freelypass-the casing. Thebitprovided by this invention-eliminates thenecessity of using underreamers and permits casing of large diameter tobe run a-maximum' depth in the well. as Another object of the inventionis to provide well tool of the character described in which the :cuttersare replaceable.

Another. object of the invention is to provide a well tool of thecharacter mentioned which may embodyany desired type of guide or pilotbit; for example, it may embody any suitable form of drag bit, coredrill, etc.

It is another object of the invention to provide a bit of the charactermentioned that is adapted to be detachably connected to a shoe on thelower end of well casingand is adapted to be detached from the shoethrough engagement by an overshot, or'the like, operated on a cable orline. 7 1

Other objects and. features of my inven- 7 tion will be best and morefully: understood from the following detailed description of a typicalform and application'of the inventi'om throughout which descriptionreference is had to the accompanying drawings, in

which: T

Fig.1 is a side elevation of the bitf'provided by this invention showingthe cutters in the operatingp-osition: Fig. 2 is a side elevationof theshoe provided by this invention showing I certain parts broken away.Fig. 3 is a longitudinal detailed sectional view of the bit in positionwithin the. shoe ready to be set. Figi 4 is a side elevationillustrating the bit in operating'position. Fi 5 is a detailedtransverse sectional view ta en substantially as indicated by line' 55on Fig.4. 7

The well tool provided by this invention includes, generally, a shoe 10.adapted to be attached to'the lower end of a string of well casing and abit proper A including a body 11 adapted to be loweredrinto the shoe.10, a sleeve 12 longitudinally shiftable. on the body, a stem 13 on thesleeve operable through its'weight to shift thesleeve downward relativeto the body, means 14; for releasably connecting the shoe and body 11against relative longitudinal movement, cutters 15 pivotally -mounted onthe body 11 shift-able between retracted'positions and extendedpositions, means 16 connecting the sleeve 12 and the" cutters 15 wherebythe cutters are operated to the extended positions when the sleeve 12 isshifted downward relative to the body, and a pilot cutter 11 on thelower end of the body.

The shoe 10 is permanently attached to the lower end of the well" casingand may be at tached to the casing in any desired manner. 7 Inaccordance'with the invention the shoe 10 1 ing position in the shoe.

acts as a part to which the bit proper may be releasably secured. Theshoe 10 is an elongate cylindrical member having a longitudinal opening17 extending completely throughout it. The opening 17 is preferably ofsubstantially the same diameter as the opening in the well casing and itis further preferred that the walls of the shoe 10 be somewhat thickerthan the walls of the casing so that the shoe has a larger outsidediameter than the casing. The exterior of the shoe 10 is preferably ofuniform diameter throughout its length. provided with three stops 18 inthe form of vertical shoulders. The shoulders 'or stops 18 are equallyspaced around the lower end of the shoe and face forward relative to thedirection of rotation of the shoe during drill ing operations. The wallsof the opening 17 are provided with a raised or inwardly pro j ectingportion 19 provided in its upper edge with recesses 20. The edges of therecesses 20 diverge upwardly so that the recesses are substantiallyV-shaped. The portion 19and the recesses 20 act as guides to properlyposition the body 10, as will be hereinafter clescribed. An annularrecess or groove 21 is provided in the wall of the opening 17 above theprojecting portion 19. It is preferred that the upper and lower walls ofthe groove 21 be at right angles to the longitudinal axis of the opening17.

The body 11 of the bit proper A is elongate and cylindrical in itsgeneral configuration and is adapted to-fit within the opening 17 of theshoe 10. The body 11 includes a central portion 22, a lower portion 23,and an upper extension or upper portion 24 of reduced diameter. Acirculation opening 25 extends completely through the body 11 extendinglongitudinally through the three body portions. The central portion 23is round in cross section and is provided with guides 26 to cooperatewith the recesses 20 in the shoe to properly position the body 11 in theshoe 10. The guides 26 have downwardly convergent edges to cooperatewith the walls of the recesses 20.

The lower portion 23 of the body 11 is of triangular cross sectionhaving three vertical'sides 27. In accordance with the inven tion thelower portion 23 of the body projects a considerabledistance below thelower end of the shoe 10 when the body 11 is in operat- The lower end ofthe portion 23 is provided with a reduced screw threaded pin 28 to whichany desired type of pilot cutter or bit may be attached. The cutters 15are pivotally mounted on the vertical faces or sides 27, as will behereinafter described.

The upper portion 24 of the body is of considerably less diameter thanthe central portion 22 so that the upper end of the portion 22 presentsan upwardly facing shoulder 30.

The lower end of the shoe 10 is- The upper end of the central portion 22may be provided with a socket 31 and the lower end of the portion 24 maybe screw threaded into the socket. An outwardly extending radial flangor enlargement 32 is provided on the upper end of the upper portion 24.

Any suitable type or form of pilot bit may be attached to the lower endof the body. In the particular form of the invention illustrated in thedrawings I have shown a core drill 33 screw threaded onto the pin 28.The core drill includes a body 34, cutters 35 pro j ecting radially fromthe body 34, an annular corecutter 36 at the lower end of the body 34,and a core tube or barrel 37 projecting upwardly in the opening 25.Fluid passages 37 a are provided in the body of the core drill todischarge fluid from the opening 25. The core drill 33 just described isa typical form of drill, and the-invention is not to be considered aslimited to this particular type of drill for a pilot or guide bit.

The sleeve 12 is longitudinally shiftable on the upper portion of thebody 11 bet-ween the shoulder 30 and the flange 32. The sleeve 12preferably has a curved exterior and freely fits within the shoe 10. Theupper end of the sleeve 12 is provided with a socket 35 having bottom orlower end which engages the flange 32 to limit the upward movement ofthe sleeve.

The stem 13 projects upward from the upper end of the sleeve 12 and isprovided to carry or depend the body 11 from a cable or line and toshift the sleeve 12 downward. rolative to the body 11 when the body isin position in the shoe 10 and the cable is released from the stem 13.The stem 13 is tubular and is comparatively long, extending aconsiderable distance upward into the casing. In practice it may beconvenient to form the stem 13 of lengths of drill pipe. The upper endof the stem 13 is provided with a releasable cable connection which isnot illustrated in the drawings, connections of this type being wellknown to those skilled in the art.

The lower end of the stem 13 may be screw threaded into the socket 35.The stem 13 is of suflicient weight to cause downward movement of thesleeve 12 when the body 11 is in position in the shoe and the cable isreleased from the stem.

The means 14 for releasably connecting the body 11 and the shoe' againstrelative longitudinal movement is actuatedby the downward shifting ofthe sleeve 12 relative to the body 11. The means 14 includes a resilientexpansible ring37 arranged around the por tion 24 of the body adjacentthe shoulder 30. The ringj37 may be formed of rubber composit-ion, orthe like, and is positioned in alignment with the groove 21. The ring isshaped to readily enter the groove and its inner side is inclinedupwardly and outwardly. A plurality of spaced metal inserts or blocksare .12- and for resisting the tendency of the fluid provided on theouter-side of thepring 37. The ring is connected to the body 11 by leafsprings 'attached-to the inu'erzsides ,of:.the

pressure in the casing to prematurely shift the sleeve downward. Acoiled spring 42 is arranged under compression between the shoulder 30and lower end of the sleeve 12.

The spring 42 normallyyieldingly urges the sleeve upward. H

The cutters 15 may be in the form of blade cutters and are pivotallymounted'on the vertical faces 27 of the lower portion of the body. Thereare preferably three cutters15, one cutter mounted on each face 27. Thecut t-ers are shiftable between positions where they do not project fromthe'body and actuated positions where their cuttingpartsprojectlaterally from the body. The cutters 15 maybe flat and are 'pivotallymounted on studs 43 projecting laterally from: the faces 27. Each cutter15 includes an inner portion having an opening 46 passingthe stud 43 anda cuttingportion 47. The cutters15 are retained on the studs 43 by meansof retaining nuts 48 screw threaded on the studs. Keys 4911135 beprovidedto lock the nuts 48 on the studs. The cutting. portion 47 ofeach-cutter projects from the innerportion so that it is shifted from aposition adjacent the face 27 to a position where it projects from thebody whenthe cutter. ispartially rotated.

, It is an'important feature of the invention that the body 11 bepositioned in the shoe 10 by the guides 26, and the cutters are locatedso thatfwhen the cutters 15v are actuated to the-extended positions theyare. adjacent to, or in. engagement with, the stops 18. r This positionof the cutters is clearly illustrated in Fig. 4 of the drawings Thecutters thus arranged are; efi'ectively supported against r0- tativestrains during operation ofthe tool. With this construction the studs 43are not subjected to undue strain and thecutters are always easilyshifted or, rotated.

The means 16 for connecting thecutters 15' with the sleeve 12 includes arod 50 pivotally attached to, each cutter, and secured i to, the sleeve.Theupper ends of the rods 50 may be screwthreaded into openings in thelower end of the sleeve. 1 The rods project downwardly fromthe sleeveand extend through longitudinal openings 51 in thecen sleeve 12 isshifted downward.

tral-v portion of the body; The rodsxelitend completely throughtheportion 22 of the body and their lower ends-areflattened.v The flat-:xtenedwlowerends of the rods '50 extend between yoked parts 52ofzthecutters15. Pivot pins53 extendthrough openings in the yoked parts52 and' the flattened portions oi the rods -50andv pivotally connect therods and cutters. .The yoked parts. 52 project from the inner portionsof the cutters and the rods are pivotallyl attached to the cutters atpoints oflset from the axes of rotation of the cutters. The rods 50-areconnected to the cuttersina manner to causethecutting. portions 47 ofthe cutters'to be swung outward when the It is believed-that theoperation of the bit provided by this invention will be-understoodfromithe foregoing detailed description: The shoe 10.is permanentlyattached to the lower end of thecasing before it is run into'the wellbore. When the casing is placed in the well the bitA is lowered into thecasing by means of a cable, or the like, removably attached to. the stem13 by a releasable cable connection. When the body 11 reachesthe shoe l0theguides26'cooperate with thenecesses 20 toproperly position the 11 andother lowering of the tool through the casingso that-the cutters remainin the retracted posit ion;v Whenthe body lliis set or positioned in.the shoe 10 the cable or line is released from thestem and :the stem ispermitted to move downward. The downward movement of the stem' 13 andthesleeve 12 shiftsthe wedge part v41 into :engagement with the taperedside/0f the rin 37and expandsthe ring and blocks'39 intot e groove 21.Downward movement of the sleeve 12 acting through the rods 50 partiallyrotates the cutters 15 so that the cutting parts 47 are moved intoactuating position. ready for operation androtation of the bus ing andshoe '10may be started. It is to be noted that the body 11 of the bitproper A is held against longitudinal movement relative to the shoe 10by the meansrland that it isxheld against relative rotative movement bythe cooperation of the stops 18 and the cutters 15 and by the guides 26.When it is desired tori'ernove or detach the bit A from the shoe 10 anovershot, or like-tool, isoperat'ed by=a cable or line to engage thestem 13 and is pulled upward. It; will be obvious how the resilent ring37 i will return 'toits normal free position and the" cutting parts 47will be swung to their normal retracted positions when the stem-13 ismoved upward. The cutters 15 are readily removed from the studs 53 forrepair or replacement. Any

on; the pin' portion 128. of the body. The

The tool is then spring 42 acts to yieldingly hold the parts in form ofmyinvention, I do not wish to limit myself to the specific details setforth, but wish to reserve to myself any changes or variationsthat mayappear to those skilled in the art or fall within the scope of thefollowing claims.

Having described my invention, I claim:

.1. A well tool of the character described including, a shoe adapted tobe attached to the lower end of a spring of well casing, and a bitadapted to be passed through the casing including, a body, means forpositioning the body 'within the shoe, means for releasably holdingthebody and shoe against relative longitudinal movement in eitherdirection, a cutter pivoted on the body, and means for swinging thecutter to a position where it projects from the body when the body ispositioned within the shoe. I 2. A well tool of the-character describedincluding, a shoe adapted to be attached to the lower end of a string ofwell casing, and a bit adapted to be passed through the casingincluding, a body, means for positioning the body within the shoe, meansfor releasably holding the body and shoe against relative longitudinalmovement in either direction and against relative rotative movement, acutter pivoted on the body, and means for partially rotating the cutterto a position vwhere it projects from the body when the bodyispositioned within the shoe.

3. A well tool of the character described including, a shoe adapted :tobe secured to the lower end of a string ofwell casing, a stop on theshoe, and a bit-adapted to be passed through the casing including, abody, means for releasably holding the body against longitudinalmovement relative to the shoe, a cutter pivotally mounted on the body,cutting parts on the cutter, and means for partially rotating the'cutterto operate the cutting parts to a position adjacent the stop.

1. A well tool of the character described including, a shoe adapted tobe secured to the lower end of a string of well casing, there being aninternal groove in the shoe, and a bit adapted to be passed through thecasing, including, a body, means for definitely positioning, the bodywithin the shoe, a cutter pivotally mounted on the body, cutting partson the cutter, and means for releasably holding the body againstlongitudinal movement relative to the shoewhen the body is positioned inthe shoe, and for shifting the out ting'parts to an extended positionprojecting from the shoe, said means including a sleeve longitudinallyshiftable on the body, means for cau sing' movement of the sleeve, anexpansible ring attached to the body and expandedinto the groove bymovement of the sleeve, and a rod connecting the cutter and sleeve.

5. A well tool of the character'described including, a shoe adapted tobe secured to the lower end of a string of well casing, there being aninternal groove in the shoe, and a bit adapted to be passed through thecasing including, a body, means for definitely positioningthe bodyWithin the shoe, a cutter pivotally mounted on the body, cutting partson the cutter, and means for releasably holding the body againstlongitudinal movement relative to the shoe when the body is positionedin the shoe, and for shifting the cutting parts to an extended positionprojecting from the shoe, said means including a sleeve longitudinallyshiftable on the body, means yieldingly retaining the sleeve in acertain position, means for causing movement of the sleeve, an.expansible ring attached to the body and expanded into the groove bymovement of the sleeve, and a rod connecting the cutter and sleeve.

6. A Well tool of the character described including, a shoe adapted tobe secured to the lower end of a string of Wellcasing, there being aninternal groove in the shoe, and a bit adapted to'be passed through thecasing including, a body, means for definitely 'positioning the bodywithinthe shoe, a cutter pivotally mounted on the body, cutting parts onthe cutter, means for releasably holding the body against longitudinalmovement relative to the shoe when the body is positioned in the shoe,including a sleeve longitudinally shiftable on the body, an expansiblering attached to the body, Wedge parts on the sleeve and gravity meansfor shifting the sleeve so that the wedge parts expand the ring into thesaid groove, and means for operating the cutter so that the cuttingparts project from the shoe. I

7. A well tool of the character described including, a shoe adapted tobe secured to the lower end of a string of well casing, there being aninternal groove in the shoe, and a bit adapted to be passed through thecasing including, a body, means for definitelv positioning the bodywithin the shoe, a cutter pivotally mounted on the body, cutting partson the cutter, means for releasably holding the body againstlongitudinal movement relative to the shoe when the body is positionedin the shoe, including a sleeve longitudinally shiftable on the body, anexpansible ring attached to the body, wedge parts on the sleeve andgravity means for shifting the sleeve so that the wedge parts expand thering into the said groove, and means for operating the cutter so thatthecutting parts project from the shoe, last m'entioned'means including, arod on the sleeve connected to the cutter.

8. A well tool of the character described including, a shoe adapted tobe secured to the lower end of a string of well casing, there being aninternal groove in the shoe, and a bit adapted to be passed through thecasing including, a body, means for definitely positioning the bodywithin the shoe, a cutter pivotally mounted on the body, cutting partson the cutter, means for releasably holding the body againstlongitudinal movement relative to the shoe when the body is positionedwithin the shoe including, a sleeve longitudinally shiftable on thesleeve, wedge parts on the sleeve, an expansible ringattached to thebody, blocks on ring, and a stem on the sleeve operable through itsweight to shift the sleeve downward and causethe wedge parts to expandthe sleeve into the groove, and a rod on the sleeve attached to thecutter.

9. A well tool of the character described including, a shoe adapted tobe attached to the lower end of a string of well casing, and a bitadapted to be passed through the casing including, a body, means forpositioning the body within the shoe, including guides on the bodyadapted to cooperate with recesses in the shoe, means for releasablyholding the body and shoe against relative longitudinal movement ineither direction, a cutter pivoted on the body, and means foroscillating the cutter to a position where it projects from the bodywhen the body is positioned within the shoe.

10. A well tool of the character described including, a shoe adapted tobe attach-ed to the lower end of a well casing, a stop on the shoefacing forward relative to the direction of operation of the casing, anda bit adapted to be passed through the casing including, a body, acutter pivotally mounted on the body, cutting parts on the cutter, meansfor definitely positioning the body within the shoe, and means forsimultaneously holding the body against movement relative to the shoeand for operating the cutter so that the cutting parts are immediatelyforward of the said stop.

from the shoe upon upward movement of the stem.

12. A well tool including, a shoe adapted to be permanently sectioned tothe lower end of a well casing, a plurality of stops on the shoe facingforward relative to the direction of rotation of the casing, and a bitadapted to be passed through the casing including, a, body, a pluralityof cutters pivotally mounted on the body, means for definitelypositioning the body in the shoe, means for releasably holding the bodyagainst longitudinal move ment relative to the shoe, means for shiftingthe cutters so that a cutter is immediately forward of each stop, and apilot cutter on the lower end of the body.

In witness that I claim the foregoing I have hereunto subscribed my namethis 26th day of September, 1929.

GEORGE G. CHALMERS.

11. A Well tool of the character described including, a shoe adapted tobe secured to the lower end of a string of well casing, there being aninternal groove in the shoe, and a bit adapted to be passed through thecasing including, a body, means for definitely positioning the bodywithin the shoe, a cutter pivotally mounted on the body, cutting partson the cutter, means for releasably holding the body againstlongitudinal movement relative to the shoe when the body is positionedwithin the shoe including, a sleeve longitudinally shiftable on thesleeve, wedge parts on the sleeve, an expansible ring attachedtothe'body, blocks on the ring, and a stem on the sleeve operable throughits weight to shift the sleeve down ward and cause the wedge parts toexpand the sleeve into the groove and a rod on the sleeve attached tothe cutter, the cutting parts being retracted and the body released

